The Fifth Century, a 42-minute work for choir and saxophone quartet by the English composer Gavin Bryars (b.1963), has been described as “music that makes eternity audible.” Bryars sets texts by the lesser-known 17th-century metaphysical poet, Thomas Traherne, dense considerations of eternity, infinity, and the omnipresence of God in the world. If that sounds like a lot of psychic heavy lifting, rest assured that the meaning of the piece comes through without closely following the texts. The harmonic language is consonant, and Bryars has created a discreet complementary role for four saxophones (soprano, alto, tenor, and baritone), performed flawlessly by the PRISM Quartet. Donald Nally is a highly experienced choral conductor—he was once chorus master for the Chicago Symphony—who leads The Crossing, a 31-member professional chorus. Both the PRISM Quartet and The Crossing are Philadelphia-based, and ECM’s recording from a hall at the Curtis Institute of Music features a generous acoustic that provides a relaxed bloom to the sonorities of both singers and saxes; it’s at once atmospheric and clarifying.